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    <title>Pointer tests</title>
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    <h2>Pointer tests</h2>

        <h3>Horizontal and vertical pointer tests</h3>
            <p>
                Vertical (image 1) and horizontal (image 2) pointer test can be used to examinated phoria.
                In this area they double functionality of classical cross and bracket tests.
                But existing of aditional non-central fusion stimulus is primary difference.
                It's external black circle.
                So examinating phoria using pointer test we receive result nearest to asociated phoria or fixation disparity.
            </p>

            <p>
                Principle of vertical and horizontal pointer test work is analogical to cross tests.
                One eye perceive immobile scale and second perceive pointer which can be move perpendicular to pointed direction:
                <ul>
                    <li>In vertical test: up (key &uarr;) or down (key &darr;).</li>
                    <li>In horizontal test: left (key &larr;) or right (key &rarr;).</li>
                </ul>
            </p>

            <p>
                For both tests result is calculated from following equation on the basics of
                pointer move from primary position <i>x</i>
                and distance from patient to screen <i>l</i>.
                <center>
                    <img src="../../images/eqnPhoria.png" />
                </center>
            </p>


         <br><br>
         <h3>Double pointer test</h3>
            <p>
                Double pointer test is shown on picture 3.
                During examination patient can independently:
                    <ul>
                        <li>Rotate vertical pointer (using keys &larr; and &rarr;).</li>
                        <li>Rotate horizontal pointer (using keys &uarr; and &darr;).</li>
                    </ul>
            </p>

            <p>
                Using this test it's possible to distinguish between phisiological cyclophoria
                and seeming cyclophoria caused by cens with cylindrical power:
                    <ul>
                        <li>Phisiological cyclophoria causes all pointers rotation with similar angle.</li>
                        <li>Seeming cyclophoria causes that rotations of horizontal and vertical pointers are different.</li>
                    </ul>
            </p>
            <p>
                Result is presented as actual angle of rotation horizontal and vertical pointer.
                Therefore interpretation is needed to make diagnosis.
            </p>

        <br><br><br>
        <center>
            <img src="../../images/testPointerVertical.png" />
            <br/>
            <i>Image 1. Vertical pointer test</i>
        </center>
        <br><br><br>
        <center>
            <img src="../../images/testPointerHorizontal.png" />
            <br/>
            <i>Image 2. Horizontal pointer test</i>
        </center>
        <br><br><br>
        <center>
            <img src="../../images/testPointerDouble.png" />
            <br/>
            <i>Image 3. Double pointer test</i>
        </center>
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